Police take Kyle's parents away after he accuses them of molestation. When the officers are shuffling Kyle's mom away, she says "but, who will take care of them," referring to Ike and Kyle . The officer responds with "their grandmother." Kyle's mom retorts "but, their grandmother's been dead for more than three years."

This is incorrect. Kyle's grandmother died in episode 310, "Korn's Groovy Pirate Ghost Mystery." This was approximately one year ago. I base this estimate on the fact that the children had only recently progressed to the fourth grade. At the time of episode 310, they were in the third grade. In that episode, Stan proposes digging up Kyle's dead grandmother to scare other children. Stan says she'll be perfect because she's only been dead for "three months." Therefore, at the time of episode 416, Kyle's grandmother had only been dead for a little more than one year, not three.

On the other hand, Kyle's mom might have been referring to a different grandmother. This, however, seems highly improbable considering that the death of a different grandmother has never been mentioned. Also, Kyle's mom would logically assume that the police were referring to the grandmother who was most recently living. Finally, in the episode titled "The Biggest Douche in the Universe," Kyle confirms that his grandmother died recently. This would denote that she died less than three years ago. Therefore, I believe this was a blooper, falling into the category of incorrect timing of events.